ARTBA's monthly report, "Value of Transportation Construction Put in Place," was compiled by Dr. Alison Premo Black, the association's chief economist. Black notes that while this represents a one percent increase over the $116-billion committed in 2011, real transportation construction activity fell well short of its 2010 peak, when $129-billion worth of construction work was "put in place" during the year, in large part because of the American Recovery and Reinvestment Act. However, rail-related funding was found to be up.

Black's analysis found that subway and light rail was up 16.7 percent to $6.6 billion, compared to $5.7 billion in 2011. Virtually all year, construction spending on transit projects exceeded the 2011 pace, including a 21 percent increase in December.

Railroad investment was up 7.3 percent to $10.3 billion, compared to $9.6 billion in 201. Black says private rail is benefiting from the growth of freight shipments, which generates a need for more maintenance.

Port investment was up 10 percent to $1.6 billion, compared to $1.5 billion in 2011.

ARTBA's analysis found that transportation construction activity accounted for 13.8 percent of all U.S. construction work put in place, down from 14.6 percent during 2011 and 15 percent in 2010.